I learnt to use these... Completely without instruction. I move my hands as I type and alternate my fingers by default.
I've tried touch typing tutorials, where I'm meant to keep my fingers within a 'zone', however it was causing my hands to cramp once I reached 90 WPM.
These little indicators are lovely for touch typing though, even if I'm not doing it 'properly'. No repetitive strain injury in my weird way of typing without looking though!